The present invention relates to a terminal and a connector using the terminal. The terminal is for fine-pitch uses and has an anti-wicking feature to control the flow of molten solder during assembly.
Coaxial cables are known as cables for transmitting high-frequency signals in portable telephones, personal computers, and the like in order to transmit a large volume of information. As shown in FIGS. 37 and 38, a typical coaxial cable 300 is composed of a signal line 306 having a centrally located inner conductor 302 covered with an inner insulator 304, an outer conductor 308 consisting of a large number of spirally wound or braided electric wires and covering the signal line 306, and an outer insulator 310 covering the outer conductor 308.
A soldering method, a pressure welding method, and other connection methods are employed in the prior art for connecting the coaxial cable 300 to a connector. When soldering is employed for effecting this connection, as shown in FIG. 39 according to the prior art, it is necessary to expose the outer conductor 308 and the inner conductor 302 by stripping off the outer insulator 310 and the inner insulator 304, twist the outer conductor 308 into a strand, and then solder the inner conductor 302 and the outer conductor 308 onto their associated terminals 312 of the connector. A portion formed by the solidification of the molten solder H (fused solder) is referred to in the art and herein as a fillet Fh.
As the types of connectors have diversified in recent years, connectors having a large number of terminals have become known. These include connectors in which the large number of terminals are arranged in parallel, with flat cables consisting of a large number of coaxial cables being connected to those terminals. When soldering a large number of coaxial cables to terminals, space constraints are encountered. In addition, the fillet must have a certain size to secure the cables with the requisite soldering strength. As described above, a fillet is a build-up of solidified fused solder. Thus, upon soldering, the fused solder flows on the terminal surface to some extent. Accordingly, a typical fillet-forming portion of the terminal is dimensioned with some margin of allowance by taking into account this flow of the fused solder on the terminal surface. Further, in a typical assembly a suitable gap must be secured between adjacent terminals to ensure that even when the fused solder flows toward an adjacent terminal, the fused solder does not reach the adjacent terminal.
However, even when a gap is secured between adjacent terminals, the gap between the terminals must be small when the terminal itself is small. These can be considered to be “fine-pitch” or narrow-pitch arrangements, and they increase the likelihood that the flow of fused solder may reach between adjacent terminals. Further, when the fused solder flows to reach even a portion of the terminal which comes into contact with the terminal of an associated mating connector paired with the connector, contact resistance increases due to the fused solder thus intervening between the two connectors, and this may become a factor for poor contact reliability between the connector and the mating connector.
One method for avoiding this problem is to fill up gaps by over-molding between the portion where soldering is performed on the terminal of a connector and the portion where respective terminals of the connector and its mating connector are connected to one another upon connecting the two terminals. However, such a manufacturing process using over-molding is extremely difficult in cases involving a narrow pitch of 0.3 mm or less. Meanwhile, the need for miniaturization has been increasing over the years, which means that the outer dimensions of connectors cannot be increased. Hence, the above problem must be overcome solely through improvements in connection components.
Prior publications exemplify teaching technologies for effecting solder connection between a connector and a coaxial cable or other such electric wire. These include Japanese Patent Publications No. JP 11-260439 A, No. JP 2002-324592 A and No. JP 06-45035 A. Also, U.S. Pat. No. 5,934,951 relates to anti-wicking conductive contrast for an electrical connector. This shows angled grooves for carrying solder during wave soldering.